JKQtPlotter/examples/simpletest_stepplots/README.md

# Example (JKQTPlotter): Step Line Plots in Different Styles {#JKQTPlotterSpecialStepLinePlot}
This project (see `./examples/simpletest_stepplots/`) simply creates a JKQTPlotter widget (as a new window) and adds a single line-graph (a sine-wave). Data is initialized from two QVector<double> objects.

The source code of the main application can be found in  [`jkqtplotter_simpletest_stepplots.cpp`](https://github.com/jkriege2/JKQtPlotter/tree/master/examples/simpletest_stepplots/jkqtplotter_simpletest_stepplots.cpp). For the most part, several datasets of cosine-curves are generated. Then graphs of type `JKQTPSpecialLineHorizontalGraph` are added to the plot:

```.cpp
	// 3 now we make several plots with different step styles, each one also contains a
    //     symbol plot indicating the location of the datapoints themselves
    JKQTPSpecialLineHorizontalGraph* graph;

    //-- JKQTPStepLeft ----------------------------------------------------------------------------------------
    graph=new JKQTPSpecialLineHorizontalGraph(&plot);

    // set data for the graph
    graph->setXColumn(columnX);
    graph->setYColumn(columnY1);

    // set step style
    graph->setSpecialLineType(JKQTPStepLeft);
    graph->setLineWidth(1);
    graph->setFillCurve(true);
    graph->setDrawLine(true);
    graph->setTitle("JKQTPStepLeft, filled");

    // enable symbols
    graph->setDrawSymbols(true);
    graph->setSymbolType(JKQTPGraphSymbols::JKQTPCircle);
    
```
Note that you can configure the step type (left/center/right by `graph->setSpecialLineType(JKQTPStepLeft)`. With `graph->setFillCurve(true)` you can draw the curve filled until the y=0-axis and with `graph->setDrawLine(true)` you can switch the line along the values on and off (e.g. to only have the filled area, but no line). With `graph->setDrawSymbols(true)` you can switch on drawing of symbols at the location of the data points.

... and all graphs are added to the plot:
```.cpp
    // add the graphs to the plot, so it is actually displayed
    plot.addGraph(graph);
```

In addition to the symbol type and line style, you can also alter the size of the symbols (`graph->setSymbolSize(14)`), the line-width used to draw them (`graph->setSymbolLineWidth(1.5)`) and the line width of the graph line (`graph->setLineWidth(1)`). If you want to switch off the line altogether, use `graph->setDrawLine(false`.

The result looks like this:

![jkqtplotter_simpletest_stepplots](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_stepplots.png)


If you use `` instead of the horizontal variant `` and exchange x- for y-data, you will get a plot like this:

![jkqtplotter_simpletest_stepplots_vertical.png](https://raw.githubusercontent.com/jkriege2/JKQtPlotter/master/screenshots/jkqtplotter_simpletest_stepplots_vertical.png)

Also note how the red graph is filled towards the y-axis, not the x-axis.